Car-spring



(No Model.) I 2 Sheets-Sheet 1.

A. MIDDLETON.

Gar Spring.

No. 229,164. Patented June 22,1880.

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A. MIDDLETON.

Car Spring. v 7

No. 229,164. Patented June 22, 1880.

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UNITED STATES PATENT OFFICE.

ALLEN MIDDLETON, OF PHILADELPHIA, PENNSYLVANIA.

CAR-SPRING.

SPECIFICATION forming part of Letters Patent No. 229,164, dated June 22, 1880.

Application filed May 17, 1880. (No model.)

'To all whom it may concern:

Be it known that I, ALLEN MIDDLETON, a citizen of the United States, residing in Phila delphia, Pennsylvania, have invented an Improvement in Oar-Sprin gs, of which the following is a specification.

My invention relates to an improvement in that class of car-springs in which spirals are combined with and interposed between plates, or are contained in a box provided with a top plate which bears on the springs; and the main object of my invention is to make springs of this class more economically than heretofore.

In the accompanying drawings, Figure 1, Sheet 1, is a vertical section of one form of car-sprin g in which my invention is embodied Fig. 2, a plan view of the bottom plate, from which the spirals have been removed; Fig. 3, Sheet 2, a vertical section of a spring, showing a modified arrangement of spirals; and Fig. 4., a plan view of the box, Fig. 3, as it appears after the removal of the spirals.

Figs. 1 and 2 represent, on a scale of half the actual size, a car-spring which I have constructed with a view of testing its capacity in comparison with a spring having precisely similar spirals, but arranged vertically in the usual manner.

A is the top plate, and B the bottom plate, of the spring, and between the two plates are interposed the two spirals D D, which are arranged at reverse but otherwise similar angles in respect to a vertical line, as. The two plates are connected together by rods to a in such a manner that the upper plate can yield under pressure to the extent desired.

On. the under side of the upper plate and the upper side of the bottom plate are found proper bearing-surfaces for the ends of the spirals, and on both plates are projections b, which, fitting freely within the said spirals, tend to maintain the same in their proper inclined positions.

It will be seen that greater steadiness in the direction of the arrows is assured when the spirals are arranged in this manner than when they are vertical; but the most important result attained is theincreased strength imparted to the spring by inclining the spirals. Without advancing any theories as to the cause of this increased strength, I will state the fact, proved by actual test, that a spring with two vertical spirals yielded to the extent of thirteen-sixteenths of an inch under a pressure of seven thousand five hundred pounds, while the spring with two inclined but otherwise precisely similar spirals yielded to the extent of five-eighths of an inch under the same pressure. The economy of my improved spring in the saving of material will be evident from the above statement.

It is not essential that the spirals of the spring should be inclined upward and inward toward each other, for precisely the same results will be attained if the spirals are inclined upward and outward; or, in other words, the spring shown in Fig. 1 might be placed upside down without any change in the result; but I prefer the arrangement of spirals shown in that figure.

My invention may be carried into effect by the construction of springs with any desired number of inclined spirals. For instance, there is a class of springs in which a box with an upper plate is combined with a large number of small spirals made of iron or steel wire.

In applying my invent-ion to this kind of spring, I adopt the plan shown in Figs. 3 and 4, in which 13 is a box having at the bottom projections, over which fit the lower ends of twenty spirals arranged in rows, there being twenty similar projections in the top A of the box for entering the upper ends of the spirals. These projections (or sockets may be used in their place) are so arranged in the bottom of the box and on the under side of the top of the same that one row of springs will be inclined in one direction, the next in the reverse direction, and so on, so that one set of spirals will resist the tendency of the other set to impart a lateral movement to the top of thebox when pressure is applied to the same, as in the spring shown in Fig. 1.

Other modifications of springs with inclined spirals will readily suggest themselves to those familiar with car-springs of the class to which my invention relates.

Spirals arranged one within the other may be used, or spirals arranged in tiers. Indeed, In testimony whereof I have signed my name my invention may be applied to almost any to this specification in the presence of two subof the springs of this class now in use. scribing witnesses.

I claim as my invention ALLEN MIDDLETON. A car-spring in which inclined spirals are Witnesses:

combined with and interposed between plates, JAMES F. TOBIN,

substantially as described. HARRY SMITH. 

